Color Vision Research Articles

Complete color vision loss in a patient with metastatic melanoma of the skin treated with nivolumab-relatlimab.

IntroductionThe combination nivolumab-relatlimab has demonstrated therapeutic benefits for patients with metastatic melanoma. However, its adverse effects can affect various organs, including the eye.Case reportWe present the case of an 80-year-old man who developed complete color blindness after the 2nd dose of nivolumab-relatlimab for advanced cutaneous melanoma. He also had significant blurry vision. Fundoscopy identified bilateral serous macular detachment. Ocular coherence tomography confirmed serous infiltration within the macula. After a thorough investigation, causality assessment linked this retinal effect to nivolumab-relatlimab (probable relationship via Naranjo criteria).Management and outcomeThe patient was treated with corticosteroids, intravenous immunoglobulin (IVIG), rituximab, and plasmapheresis, with improvement in blurry vision. However, he continued to experience persistent absence of color perception ("black and white vision") at a follow-up visit six months later.Discussion/conclusionFurther studies are necessary to understand the exact pathophysiology of this process. We hypothesize that it involves direct toxicity to the photoreceptors or retinal ganglion cells, leading to irreversible color vision loss. Effective strategies for preventing this significant, life-changing toxic effect of nivolumab-relatlimab should be sought.

Impact of blepharoptosis surgery on vision-related quality of life and its correlation with contrast sensitivity changes.

To investigate the correlation between contrast sensitivity changes and post-surgical improvement in visual function perception and health-related quality of life among patients with blepharoptosis. This prospective cohort studied 55 patients with blepharoptosis surgical indication, one eye per patient was considered for analysis. Refraction, visual acuity (VA), eyelash ptosis and contrast sensitivity (CS) test were evaluated. The National Eye Institute Visual Functioning Questionnaire-25 (NEI-VFQ25), concerning vision-related activities and symptoms, was used to assess the patient´s quality of life pre and postoperatively. Patients were analyzed globally and divided according to the severity of ptosis, lens opacity and the co-existence of glaucoma. 55 eyes underwent ptosis surgery. VA significantly improved without notable refractive changes (p = 0.0044). CS demonstrated significant enhancement in all patients and groups. The NEI-VFQ 25 overall score significantly improved from baseline to 3months postoperatively (p < 0.001). General vision (p = 0.0319), near and peripheral vision (p < 0.001 and p = 0.0188, respectively), color vision (0.0177), ocular pain (p < 0.001), dependence (p = 0.0093) and mental health (p = 0.0341) exhibited significant improvement. All groups experienced a significant increase in the overall score postoperatively. They all concurred on the improvement of the subscale near vision, except for the glaucoma group, which showed no improvement in either of the subscales. Ptosis surgery significantly improves contrast sensitivity, visual function, and quality of life in patients, including those with ocular comorbidities such as lens opacity and glaucoma. NEI-VFQ 25 assessment revealed an important enhancement in near and peripheral vision, ocular pain, and dependence; which highlight the broad benefits of the surgery, increasing autonomy in daily activities.

Modeling spatial acuity improves trap capture of western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae).

Colored sticky traps are used for management of many common agricultural insect pests. Several recent studies have shown that traps can be improved by systematically considering properties of color vision for the target species. In the current study, we extend this approach to spatial vision, using information about the interommatidial angle of an agriculturally important insect pest, western flower thrips Frankliniella occidentalis (Pergande), to predict spatial resolution capabilities for a yellow flower pattern across a range of viewing distances. We tested the hypothesis that pattern sizes matching the spatial resolution capabilities of western flower thrips at a given viewing distance would outperform traps with mismatched pattern sizes by measuring the number of western flower thrips caught on sticky traps containing differently sized flower patterns resolvable at 5, 10, or 20 cm. We found an interaction between pattern size and viewing distance, with significantly more western flower thrips caught on traps when the predicted resolvable distance of the pattern matched the distance traps were placed from a central release point. We further tested the range over which trap patterns are effective in more complex viewing environments using commercial polytunnels. In polytunnel trials, we found that increasing the resolvable distance of patterns increased western flower thrips capture up to approximately 26 cm, after which western flower thrips capture decreased up to the maximal visible range tested (50 cm) in the absence of additional sensory cues. Together, these results show the utility of considering spatial vision in improving trap performance and offers functional insights to improve pest management in visual trap design.

The innovative DEA application for color vision self-re-education of eyes suffering from dyschromatopsia

Dyschromatopsia is a disorder involving difficulty or inability to recognize color distributions and distinguish between shades of different colours in severe cases. Recently, a non-invasive algorithmic technique for its diagnosis and monitoring has been proposed. Based on these results, in this paper, the DEA (Dyschromatopsia re-Education Algorithm) algorithm for the re-education of the eye to color vision is presented through a training path that exploits brain plasticity. DEA has also been converted into an app in order to run on personal smartphones. Also, for this reason, the use of DEA can take place without the help of a professional figure. After the diagnostic phase in which type and severity of dyschromatopsia are assessed, the algorithm proceeds with eye re-education by exploiting the brain’s plastic readjustment ability. The re-education method is based on the standard artificial intelligence learning model. Eye re-education shows progressive improvement in visual color ability and color distribution. Moreover, the achieved results appear to be permanent (at least within three months after training). This study represents a proof of concept for the proposed re-educational method. The results from the pilot experimentation are promising and demonstrate the feasibility of the approach. Future studies on a larger scale, in collaboration with clinical experts, will be necessary to validate and optimize the methodology.

Behavior-Specific Computations in the Vertebrate Retina.

Since Lettvin and colleagues' seminal discovery of bug detector neurons in the frog retina, understanding how retinal circuits support behavioral demands has been a central goal of visual neuroscience. Recent advances in machine learning, genetic tools, and neural recording have transformed our understanding of these circuits, particularly in the mouse retina. With a focus on mice, we examine how species-specific visual sampling strategies determine the behavioral relevance of retinal computations and review recent insights into circuits underlying reflexive behaviors, threat detection, prey capture, color vision, and night vision. We also highlight how the behavioral state itself influences retinal processing through direct neuromodulation and pupillary changes, challenging the traditional view of purely feedforward retinal processing in mammals. These findings confirm the retina as a sophisticated computational engine whose circuits have evolved to meet species-specific behavioral demands. While Lettvin's discovery of dedicated retinal circuits for innate behaviors launched the field, new tools now promise to expand our understanding of retinal contributions to naturalistic and flexible behaviors across species.

New Simple and Fast Digital Screening Method for Minimal Hepatic Encephalopathy in Cirrhotic Patients

ABSTRACTCovert hepatic encephalopathy (CHE) is a subtle yet significant neurological complication of liver diseases, especially in patients with cirrhosis. Although it lacks overt clinical signs, CHE severely impacts quality of life, increases accident risks, and has serious prognostic implications. It is characterized by neurocognitive symptoms detectable only through specialized neuropsychometric tests. CHE affects 30%–80% of cirrhotic patients and represents the early stage of hepatic encephalopathy, which is a predictor of mortality. Early diagnosis is essential to improve patient outcomes. The Psychometric Hepatic Encephalopathy Score (PHES) is the gold standard for diagnosing CHE, but it is time‐consuming and requires specialized training. Other tests, like the Animal Naming Test (ANT), are simpler and more practical for screening minimal hepatic encephalopathy (MHE), though they lack specificity. The Stroop test shows promise as a quicker and reliable diagnostic tool, but still has limitations. Recent innovations include a smartphone‐based self‐screening method developed by Dobbermann et al., combining three digital tests: the Tip Test, Number Connection Test, and Modified Stroop Test. This approach correlates well with PHES, is independent of language skills, and is accessible for a diverse patient population, including those with color vision deficiencies. This tool offers a rapid and reliable way to screen for CHE even in home settings, potentially improving early detection and intervention. In conclusion, CHE is an underrecognized but critical condition that requires greater clinical attention. Current diagnostic tools have limitations, highlighting the need for more effective, practical methods. A multidisciplinary approach involving hepatologists, neurologists, and neuropsychologists is crucial to improve the diagnosis and management of CHE, ultimately enhancing patient outcomes.

Color vision-associated environmental and biological factors in the development of myopia.

Color vision-associated environmental and biological factors in the development of myopia.

Specific transcription factors regulate the expression of Rh6 in Bactrocera minax and Bactrocera dorsalis (Diptera: Tephritidae).

Specific transcription factors regulate the expression of Rh6 in Bactrocera minax and Bactrocera dorsalis (Diptera: Tephritidae).

Clinical and radiological presentation of meningiomas.

The purpose is to analyze the clinical and radiological presentation of meningiomas in an Indian population in a tertiary eye care institute in South India. A total of 15 patients with intraorbital and intracranial meningioma presented to our neuro-ophthalmology clinic over 4 months. These cases of meningioma presented primarily to us with ophthalmic features and were diagnosed by us. Complete neuro-ophthalmic evaluation, including ocular examination, fundus, color vision, visual field, cranial nerve examination, was performed for each case and neuroimaging in the form of MRI brain with orbit with contrast. Clinical presentation of each case and site and extension of meningioma in neuroimaging was analyzed. Among 15 patients, age range was from 26-72 years, with mean age of 56 years. A total of 27% of patients were male, and 73% were female. A total of nine out of 15 cases were histologically proven. Chiasmal compression was observed on neuroimaging in 53% of patients. A total of 10 patients (66.67%) presented with complaints of defective vision, and five patients (33.33%) had double vision as their presenting symptom. Clinical examination revealed signs of sixth cranial nerve involvement in 20%, multiple cranial nerve paresis in 20%, and third cranial nerve palsy in 13%. A total of 47% of patients did not have any cranial nerve involvement. Visual field examination revealed homonymous hemianopia in 13% of patients. On fundus examination, 40% had bilateral optic atrophy, and 7% presented with papilledema. Visual field defects were documented and corelated with location of meningioma. Our study emphasizes the role of ophthalmologists in early detection of meningioma as many patients present first with subtle ophthalmological signs and symptoms before developing neurological symptoms.

Statins and Thyroid Eye Disease: A Propensity Score-Matched Retrospective Cohort Analysis.

Background Thyroid eye disease is a sight-threatening disorder associated with Graves's disease. While treatment is aimed at stabilizing established thyroid eye disease, there are limited investigations regarding prevention. Statins, known for their anti-inflammatory properties, are one such treatment that has been investigated for thyroid eye disease. This study retrospectively analyzes the impact of statin medications on thyroid eye disease and related outcomes from real-world data using TriNetX Global Collaborative Network(TriNetX, Cambridge, MA, USA). Objective The primary objective of this study is to analyze the risk of developing thyroid eye disease in patients with Graves' disease treated with statin medications relative to those without exposure up to five years. Secondary objectives of this study include analyzing thyroid eye disease-related outcomes, including diplopia, optic nerve surgery, optic nerve injury, strabismus, blindness, requirement for teprotumumab, color vision deficiencies, and referral to ophthalmology. Methods Data were collated utilizing TriNetX Global Collaborative Network, a platform of globally de-identified patient information from over 140 healthcare organizations. Patients more than 18 years of age with a diagnosis of Graves' disease (ICD-10: E05.0 Thyrotoxicosis with Diffuse Goiter) were divided into Cohorts A (administration of statin medication following diagnosis of Graves' disease, n = 66,444) and B (no statin medication administration, n = 225,905). Via implementation of propensity score matching to control for confounding factors, a total of n = 43,025 matched patients per cohort was obtained. Hazard ratios (HRs) and 95% confidence intervals (CIs) were used to assess the primary and secondary objectives over a five-year follow-up period. The t-test was used for the calculation of mean averages of ophthalmology referrals and to determine statistical significance. Results Patients treated with statin medications (Cohort A) demonstrated a significantly lower HR for the development of exophthalmos (HR = 0.559, 95% CI 0.521-0.601, p < 0.001). Statin medications were furthermore associated with a reduced HR for diplopia (p < 0.001), optic nerve surgery (p = 0.018), and requirement for teprotumumab (p = 0.047). No significant reduction in hazardsfor color vision deficits, strabismus, optic nerve injury, or blindness was noted. Additionally, there was no significant difference in referrals to ophthalmology. Conclusion The findings from this study suggest that statin therapy may be protective against the development of thyroid eye disease and associated complications. Further randomized controlled trials are required to validate these findings and establish a therapeutic role for statins in thyroid eye disease.

Mechanisms of carotenoid metabolism: understanding the links between red coloration, cellular respiration, and individual quality.

In many species of birds, red carotenoid coloration serves as an honest signal of individual quality, but the mechanisms that link carotenoid coloration to animal performance remain poorly understood. Most birds that display red carotenoid coloration of feathers, bills, or legs ingest yellow carotenoids and metabolically convert the yellow pigments to red. Here, we review two lines of investigation that have rapidly advanced understanding of the production of red carotenoid coloration in birds, potentially providing an explanation for how red coloration serves as a signal of quality: the identification of the genes that enable birds to be red and the confirmation of links between production of red pigments and core cellular function. CYP2J19 and BDH1L were identified as key enzymes that catalyze the conversion of yellow carotenoids to red carotenoids both in the retinas of birds for enhanced color vision and in the feathers and bills of birds for ornamentation. This CYP2J19 and BDH1L pathway was shown to be the mechanism for production of red coloration in diverse species of birds and turtles. In other studies, it was shown that male House Finches (Haemorhous mexicanus) have high concentrations of red carotenoids within liver mitochondria and that redness is positively associated with mitochondrial function. These observations suggested that the CYP2J19 and BDH1L pathway might be tightly associated with mitochondrial function. However, it was subsequently discovered that male House Finches do not use the CYP2J19 and BDH1L pathway to produce red pigments and that both CYP2J19 and BDH1L localize in the endoplasmic reticulum, not the mitochondria. Thus, we have the most detailed understanding of links between cellular function and redness in a bird species for which the enzymes to convert yellow to red pigments remain unknown, while we have the best understanding of the enzymatic pathways to red in species for which links to cellular function are largely unstudied. Deducing whether and how signals of quality arise from these distinct mechanisms of ornamental coloration is a current challenge in for scientists interested in the evolution of honest signaling.

Clinical Applications of the Cone Contrast Test in Ophthalmology and Neurology.

Color vision is a critical aspect of human visual perception, yet traditional assessments often lack quantitative precision. The Rabin Cone Contrast Test and its successors offer objective, standardized measurements of cone-specific contrast sensitivity. These tests improve the detection and classification of color vision deficiencies and can facilitate the monitoring of color vision deficits in inherited retinal diseases, cone dystrophies, optic neuropathies, and brain injuries. Integrating quantitative color vision testing into clinical practice presents a more reliable, reproducible, and functionally relevant evaluation, highlighting its value in disease diagnosis, characterization, and management.

Is Primate Cone Ratio Variation Functional and Adaptive?

Variation in animal perception provides excellent opportunities for studying adaptation. Unusually, primates exhibit a great deal of inter- and intra-specific visual system variation. Here, we discuss what is known about the retinal cone mosaic, and the sources of variation in primate cone types and their relative expression. We focus on catarrhines (African and Asian monkeys and apes and humans), which have evolved uniform trichromacy, exhibiting short- (S), medium- (M), and long-wave (L) cones. Catarrhines generally exhibit high inter-specific consistency in the peak sensitivities of their L and M sensitive cones. One under-explored component of variation is the relative expression of those cones, that is, the L:M ratio. Across catarrhines, the mean L:M ratio is 1:1, with some limited intraspecific variation. Intriguingly, humans show two big differences compared to other catarrhines. Firstly, their mean L:M ratio is shifted to 2:1. Secondly, they show vast (75-fold) intraspecific L:M ratio variation. We discuss evidence as to whether this difference in the mean ratio, and this high intraspecific variation, are likely to have functional consequences, concluding that indeed this variation likely impacts color perception. We finish by suggesting possible explanations for the higher mean ratio of L:M cones in humans, highlighting similarities with other aspects of our color vision that differ from other catarrhines. We hope that the suggestions and questions we raise will inspire future research on primate cone ratios.

Comparison of Heidelberg Multi-Color Anomaloskop with NEITZ anomaloscope OT-II to diagnose color-vision deficiency.

To determine the degree of agreement between the results of the Heidelberg Multi-Color Anomaloskop (HMC) and NEITZ anomaloscope OT-II (OT-II). Retrospective. The study included 53 patients who underwent color-vision testing at Kariya Toyota General Hospital between March 2019 and April 2022. The participants included 2 patients with normal color vision, 10 with protanopia, 3 with protanomaly, 22 with deuteranopia, and 16 with deuteranomaly. Color-vision testing was performed using the Ishihara Test for Colour Deficiency, Standard Pseudoisochromatic Plates Part 1, Farnsworth Dichotomous Test for Color Blindness Panel-15, HMC, and OT-II. An agreement was determined using intraclass correlation coefficients (ICC) and Bland-Altman analysis. The minimum, median, and maximum red-green mixture and yellow monochromatic values of the equal values obtained from HMC and OT-II were examined. The ICCs between the results of HMC and OT-II were 0.979, 0.979, and 0.985, for the minimum, median, and maximum red-green mixture and 0.943, 0.755, and 0.919 for the yellow monochromatic values, respectively (p<0.0001 in all). In the Bland-Altman analysis, the differences were mostly within the limits of agreement. Fixed errors were observed for the maximum red-green mixture and minimum yellow monochromatic values. Proportional errors were observed for the maximum red-green mixture and yellow monochromatic values. HMC and OT-II showed high agreement for all values in the ICC and Bland-Altman analyses. In the Bland-Altman analysis, systemic errors were observed in the maximum red-green mixture value and the minimum and maximum yellow monochromatic values.

Adjustable Plasmonic Core–Shell Nanoparticles for Personalized Color Vision Correction

Color vision deficiency (CVD) is a visual impairment caused by the inability of certain retinal cone cells to detect specific wavelengths of light, leading to challenges in color discrimination. Conventional corrective methods, such as tinted lenses, provide limited effectiveness due to individual variability in cone sensitivity. To address this, customized contact lenses are developed embedded with core‐shell nanoparticles, where the localized surface plasmon resonance (LSPR) is tuned by adjusting the proportion of Au and Ag in the shell. The nanoparticles, with an average core size of 11 nm and a total diameter of 42.25 nm, exhibit absorption peaks spanning from 400 to 550 nm. Contact lenses incorporating these nanoparticles show reduced transmittance in the 420–580 nm range, overlapping with wavelengths critical for correcting red–green (520–580 nm) and blue–yellow (440–500 nm) deficiencies. Simulations demonstrated that the selective wavelength filtering induced by the lenses effectively modulates hue perception, highlighting their potential to enhance color discrimination and improve visual accuracy in individuals with color vision deficiencies. This personalized approach holds potential for improving visual experience in individuals with red–green or blue–yellow deficiencies, offering a promising step toward future applications in CVD correction.

An Examination Method of Color Vision Deficiency Based on Cone Fundamentals Reconstruction

ABSTRACT Various methods, including the Farnsworth – Munsell 100 hue test, Ishihara test, Nagel anomaloscope, etc. have been proposed for diagnosing color vision deficiency. Despite their prevalence, these methods exhibit potential misjudgments in diagnosis. This inherent limitation stems from the oversight of individual differences in physiological parameters of the human visual system within the population. This paper introduces a color vision deficiency examination method based on the reconstruction of LMS cone fundamentals. The cone fundamentals are derived from the optimization of seven physiological parameters using matching results of multiple color pairs, categorized into three groups: Rayleigh match, Moreland match, and white match. All the pairs within each group vary in the peak wavelength of the narrow-band primary, except for the white channels, which have broader bandwidths. The accuracy of reconstructed cone fundamentals has been verified through k-fold cross-validation. The reconstructed cone fundamentals provide a basis for the accurate estimation of the type and severity of color vision abnormalities. Importantly, it has been demonstrated that the diagnosis results are consistent with those obtained by the Ishihara test, RCCT, BCVT, and CBC test confirming the reliability of the proposed methodology.

Computer Vision and Transfer Learning for Grading of Egyptian Cotton Fibres

Egyptian cotton fibres have worldwide recognition due to their distinct quality and luxurious textile products known by the “Egyptian Cotton“ label. However, cotton fibre trading in Egypt still depends on human grading of cotton quality, which is resource-intensive and faces challenges in terms of subjectivity and expertise requirements. This study investigates colour vision and transfer learning to classify the grade of five long (Giza 86, Giza 90, and Giza 94) and extra-long (Giza 87 and Giza 96) staple cotton cultivars. Five Convolutional Neural networks (CNNs)—AlexNet, GoogleNet, SqueezeNet, VGG16, and VGG19—were fine-tuned, optimised, and tested on independent datasets. The highest classifications were 75.7%, 85.0%, 80.0%, 77.1%, and 90.0% for Giza 86, Giza 87, Giza 90, Giza 94, and Giza 96, respectively, with F1-Scores ranging from 51.9–100%, 66.7–100%, 42.9–100%, 40.0–100%, and 80.0–100%. Among the CNNs, AlexNet, GoogleNet, and VGG19 outperformed the others. Fused CNN models further improved classification accuracy by up to 7.2% for all cultivars except Giza 87. These results demonstrate the feasibility of developing a fast, low-cost, and low-skilled vision system that overcomes the inconsistencies and limitations of manual grading in the early stages of cotton fibre trading in Egypt.

Color Vision 2025: Introduction by the feature editors

Color Vision 2025: Introduction by the feature editors

Investigating colour vision and its structural correlates 15 years following a first demyelinating event

BackgroundWe investigated the long-term colour and contrast vision outcomes, 15 years after a first demyelinating event, with their structural correlates using optical coherence tomography (OCT) and brain MRI.MethodsPatients recruited with...

Assessment and Outcomes of Pediatric Optic Neuritis in a Tertiary Children's Hospital in the United Kingdom: A 10-Year Retrospective Review.

AimTo define the clinical presentations, visual outcomes, and treatment practices for pediatric optic neuritis at a tertiary children's hospital in the United Kingdom.MethodsA retrospective review was conducted for patients aged 0-16 years diagnosed with optic neuritis over a 10-year period. Demographic and clinical data were retrieved from electronic and archived medical records. Follow-up assessments were completed at intervals of 2 weeks, 3 months, 6 months, 1 year, and 3 years, with a minimum follow-up of 2 weeks.ResultsSixteen patients experienced their first optic neuritis episode, with 81% presenting unilaterally and 19% bilaterally. All patients reported visual loss or blurring; headache, eye pain, and dizziness were also common. Poor visual acuity (>0.3 logMAR) was noted in 78% of eyes at presentation. Relative afferent pupillary defects were observed in 85% of unilateral cases, and initial color vision deficits were present in 64%. Disc swelling affected 46% of unilateral cases. Treatments varied, with all bilateral cases receiving intravenous methylprednisolone followed by oral steroids; 62% of unilateral cases received similar treatment. No optic neuritis recurrences were noted within the study period. Final visual outcomes did not significantly differ across myelin-oligodendrocyte glycoprotein-positive, multiple sclerosis-associated, and isolated pediatric optic neuritis groups.ConclusionPatients with pediatric optic neuritis present with initial poor visual acuity, from which the majority substantially improve within 3 months, though significant further recovery may occur up to 1 year post-presentation. Myelin-oligodendrocyte glycoprotein-positive disease appears to be a significant cause of pediatric optic neuritis. Treatment practices show significant variability; however, the trend for intravenous corticosteroid use continues to predominate.